Final answer:
The truth of the statement about the door thickness and material is not guaranteed without specific building codes and is unrelated to the physics problem provided. The physics problem concerns calculating heat flow through a wall, which involves temperature differences and combined R-values of different materials.
Step-by-step explanation:
True or false: The door between an attached garage and a dwelling unit should be of solid wood not less than 2 inches thick. This question deals with building code requirements which typically dictate that the door between an attached garage and the house must be fire-rated for safety reasons. However, the question about the thickness and material of the door is unrelated to the physics problem provided about calculating heat flow through a wall.
If we consider typical building codes, the statement can be true as many codes require the door to be a solid wood door (or a door with a solid core) that is at least 1-3/8 inches thick, or the door should have an equivalent fire rating. However, the precise thickness of 2 inches may or may not be a requirement depending on the local building regulations. Therefore, without specific reference to a local building code, the statement's accuracy is uncertain.
Concerning the physics problem in (a), the rate of heat flow through a wall can be calculated using the temperature difference and the overall R-value of the wall's layers, which is not directly related to the door mentioned in the T/F statement.
For part (b), heat flow is again calculated similarly, but this time accounting for the thermal bridges created by the wooden studs, which have different insulative properties compared to the fiberglass batts. This is a more realistic scenario, as it takes into consideration the thermal bridging effect of the studs on the wall's overall insulation.